The growth kinetics of CsPbBr₃ microwires on mica: an in situ investigation

Abstract

1D all-inorganic perovskites microwires horizontally aligned on mica show great potential in high performance optical and optoelectronic devices. In spite of the tremendous progress in their growth and properties studies, the growth mechanism for epitaxy of perovskites microwires on mica has not been well understood. Herein, we present a home-built in situ growth monitoring system to study the growth mechanism of the CsPbBr3 microwires on mica with the physical vapor deposition (PVD). Through in situ monitoring the growth of the CsPbBr3 microwires, the detailed growth behavior can be directly investigated. It is found that the length growth rate of the microwires may be enhanced with the large undercooling (the temperature difference between the precursor and the deposition substrate), which provides the possibility to achieve the rapid growth of the wires. Additionally, CsPbBr3 microwires with smaller diameter show the higher growth rate than that with larger diameter, which is consistent with the theoretical analysis based on the adatom diffusion. By increasing the undercooling, CsPbBr3 microwires with the length up to 200 μm can be grown in 15 s, which is more efficient than the traditional vapor growth routes. Furthermore, the photoluminescence and high performance of the photodetector device based on these CsPbBr3 wire arrays indicate that the as-grown CsPbBr3 wires have the potential in the optical and optoelectronic device applications.

Epitaxial Growth of 2D Bi2O2Se Nanoplates/1D CsPbBr3 Nanowires Mixed‐Dimensional Heterostructures with Enhanced Optoelectronic Properties

“…Additionally, the tetragonal symmetry of Bi 2 O 2 Se makes that the CsPbBr 3 wires epitaxially grow along two perpendicular directions parallel to the two equivalent directions of [200] Bi2O2Se and [020] Bi2O2Se , respectively (see Figure 1c and Figure S4, Supporting Information). Comparing with previous reports for epitaxial growth of CsPbBr 3 arrays, including sixfold symmetric CsPbBr 3 wire arrays on mica, [ 19 ] twofold symmetric CsPbBr 3 wire arrays on annealed sapphire [ 22 ] and uniform CsPbBr 3 plate arrays on SrTiO 3 , [ 23 ] our fourfold symmetry CsPbBr 3 wires on Bi 2 O 2 Se provide a new pattern for in‐plane epitaxial growth of CsPbBr 3 arrays.…”

“…Detailed characterizations for the pre‐prepared CsPbBr 3 film are shown in Figure S1, Supporting Information. The short space for the mass transport of CsPbBr 3 precursor is favorable for achieving high supersaturation of vapor‐phase precursors even at the heating temperature of 330 °C that is much lower than 680 °C, which not only promotes the epitaxy of CsPbBr 3 nanowires under the drive of the undercooling (Δ T , the temperature difference between precursor and depositing substrate), [ 19 ] but also prevents the damage of the pre‐grown Bi 2 O 2 Se nanoplates. The Raman spectra measured before and after the epitaxy of CsPbBr 3 wires show no obvious change of the peak position and the full width at half maximum (HWHM) for the A 1g modes (159 cm −1 ) of Bi 2 O 2 Se (see Figure S2, Supporting Information), which proves the quality consistency of the pristine and heterostructured Bi 2 O 2 Se plates.…”

“…Comparing with the pristine Bi 2 O 2 Se nanoplate possessing the smooth surface, after the deposition of CsPbBr 3 , several wires were found to be aligned on the surface of Bi 2 O 2 Se nanoplate with the length direction parallel to the edge of the square, demonstrating the well‐defined in‐plane fourfold‐symmetry orientations for the wires, which is indicative of substrate‐dependent epitaxial growth. [ 19 ] Figure 1d gives the corresponding dark‐field image of Figure 1c under the wide illumination of 405 nm laser (the dashed frame in Figure 1d marks the Bi 2 O 2 Se plate). The uniform green emission along whole wires suggests the high quality of the epitaxial CsPbBr 3 wires.…”

Graphoepitaxy of Large Scale, Highly Ordered CsPbBr3 Nanowire Array on Muscovite Mica (001) Driven by Surface Reconstructed Grooves

“…The incommensurate epitaxy is preferred, due to large commensurate lattice mismatch between CsPbBr 3 and muscovite (>50%); the optimal epitaxy model is CsPbBr 3 [100]//muscovite [100], [110] or [101] (Figure 3a, middle panel). [ 17 ] As shown in Figure 3b (upper panel) and Figure 3c (violet), at T s = 520 °C, the orientation of NWs, [100] direction, is evenly aligned with the three directions, following the quasi‐hexagonal symmetry with an orientation proportion of ≈33%, 35%, and 32% for the [100], [110], and [101] directions, respectively. The mechanism was widely reported in the growth of CsPbBr 3 NWs as well as the other inorganic crystals, which was mostly accompanied by high‐temperature growth.…”

“…Thus, as a consequence of the atomic‐level flatness, it has become one of the most frequently used substrates in van der Waals epitaxial technologies. A variety of emergent materials, including II–VI/III–V semiconductors, [ 6–9 ] transition metal dichalcogenides, [ 10 ] metal halide perovskites, [ 11–19 ] topological insulators, [ 20 ] and oxides, [ 21 ] were grown on muscovite (001) in the past decades. These single crystals exhibited superior optoelectronic and electronic properties, compared to those grown on nonlayered substrates.…”